Modern Purple Machine Cancels

The USPS authorized the use of purple ink for machine cancels in 1972 (?) and ordered a cease and desist of purple ink cancels in 1984 after the embarrassing discovery that it was extremely easy to wash these cancels off using common household chemicals and then to reuse the stamps and postal stationery.

Does any know the earliest use date for these cancels or some place I can seek that information?

Although this doesn't answer your specific question, here's a previous link containing further information on these purple cancels:

https://goscf.com/t/35123

Someone with this book probably has the answer:

http://www.ebay.com/itm/PMCs-A-Guid...331291644681

jobi01, The book that wt1 is referring to was written by Robert Washburn. He is also the person that runs the "modcoverguy" website. If you contact him at www.modcoverguy.com you may very well get your answer!

Peter

wt1: Thank you for the info on the book. I had already searched the forum and read that thread before posting.

Peter: Thank you, I will pursue that lead.

The APRL is 5 minutes away but unfortunately not open on the weekend and my day job is interfering with visits during the week.

I contacted Robert Washburn and he verifies that this is the new EDU for the purple cancel.

I'm way more of a pre-1900's kinda guy, but that's very cool. Congrats on your find and the ability to recognize its potential, now verified !